Securities Purchase Agreement (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Fair values of derivative liabilities
Derivative liabilities	$ 13,806	$ 15,270
Series D-1 Warrants [Member]
Fair values of derivative liabilities
Derivative liabilities	588	2,539
Series D-2 Warrants [Member]
Fair values of derivative liabilities
Derivative liabilities	5,621	5,266
Embedded derivatives of series C-1 preferred including dividends paid in Series C-1 Preferred [Member]
Fair values of derivative liabilities
Derivative liabilities	3,408	3,628
Embedded Derivatives of accrued dividends payable in Series C-1 Preferred [Member]
Fair values of derivative liabilities
Derivative liabilities	654	52
Series C-2 Preferred [Member]
Fair values of derivative liabilities
Derivative liabilities	$ 3,535	$ 3,785